1. Field of the Invention
This invention relates to the field of wound capacitors and in particular to capacitors having high thermal energy transfer.
2. Prior Art It is known to form capacitors by winding layers of metallized film around a core. When electrical current is passed through the capacitor winding, thermal energy is generated. In high current applications, this thermal energy can be quite large and may lead to deterioration of the capacitor. This problem is especially severe for small capacitors in which the thermal energy is concentrated in a small volume.
Additionally, this problem may be increased if the capacitor is hermetically sealed because the hermetic sealing may make it more difficult for the heat to be transferred to the exterior of the capacitor and to dissipate. It is known to place metal cover seals at the opposite ends of hermetically sealed capacitors thereby increasing somewhat the transfer of thermal energy to the exterior of the capacitor. It is further known to provide perforations in these cover seals. The perforations also facilitate the manufacture of these capacitors by permitting outgassing to occur when the capacitor is baked prior to sealing to clean and dry the capacitor. These perforations are adapted to receive solder during subsequent manufacturing steps.